If someone develops a fever after returning from a Yellow Fever zone, the most important guidance is to seek medical care immediately and clearly inform the doctor or emergency staff about recent travel to an affected area. Early disclosure helps healthcare professionals quickly consider Yellow Fever and other travel-related infections, ensuring fast diagnosis and proper treatment. Going to the ER is strongly recommended if the fever is high, symptoms worsen, or there are warning signs like vomiting, jaundice, severe headache, or bleeding.